Under the Achaemenid Empire, the northwest corner of Asia Minor, still occupied by Phrygians but mainly by Aeolians, was called Phrygia Minor and by the Greeks Hellespontus.
After Rome's defeat of Antiochus the Great in the Roman-Syrian War, the area, which had been held by the Seleucid Empire passed to Rome's ally, the kingdom of Pergamon, and, on the death of King Attalus III in 133 BCE, to Rome itself, which made it part of the province of Asia and, later, a separate proconsular province, called Hellespontus.